That's why is better to save some funds (which is known as reserve funds) in case any dip occurs one can purchase the dip with the use of reserved funds, and he or she can choose to spread it out or go all in with the reserve funds like lump-sum purchases.
There may be absolutely no need for a brand new investor, and maybe someone in their first few years of buying/acumulating bitcoin to employ buying the dip strategies rather than sticking with straight-forward and regular DCA (which may well not even be sticking with any particular amount of BTC, but instead figuring out how much BTC to buy each week from the amount of disposable income that he has for that particular week, whether that is $100 or $10 or some other amount).
Yet of course, there might be some psychological reasons to hold some money aside for buying the dip, but it may or may not end up paying off because we cannot rely on dips actually happening or even happening to such an extent that it is even going to make much of a meaningful difference in a person's bitcoin journey, especially if the person might be new to investing and ONLY investing around 10% of his/her income so it could take a whole 10 years to have 1 years of income invested into bitcoin.. so it is difficult to understand and/or appreciate what value might have had come from buying the dip rather than just buying regularly and not changing behaviors based on factors that might be difficult to measure the extent to which there might have been any kind of advantage to straight-forward DCA.
Thinking about the dip will always slow your investment so is better you forget about it and focus on accumulating as many Bitcoin as you can because procrastinating about something you don't even know will happen in the next 2 years is very wrong it will always slow you down if we all have the mindset that there's nothing like dip in Bitcoin you will see how far we will all go this mindset of dip is really drawing a lot of people back especially newbies.
The dip is characterized by a noticeable decline or fall in price of an asset which could either take place within a short or long period of time, a dip can be sudden it can as well take a long time which is not as considerably 2 years as you imply. Yeah waiting for a dip before making purchase can be a very wrong approach especially for a newbie that is meant to be accumulating Bitcoin without having anything to do with the market condition. However, combination of strategies can be good with a proper planning such that any one that is already accumulating Bitcoin with dca can as well buy the dip if it has been well figured out such that it will not affect your consistent dca and your various aspects living expenses, as buying the dip give the opportunity of buying more quantity of Bitcoin with the same amount of money as when compared with buying from it previous high.